Diagnostic Procedure

STEP	INSPECTION		ACTION
1	IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA (MODE 2) Perform the Freeze Frame PID Data Access Procedure. (See ON-BOARD DIAGNOSTIC TEST .) Is the DTC P0171:00 on FREEZE FRAME DATA (Mode 2)?	Yes	Go to the next step.
1		No	Go to the troubleshooting procedure for DTC on FREEZE FRAME DATA (Mode 2). (See DTC TABLE .)
2	VERIFY FREEZE FRAME DATA (MODE 2)/SNAPSHOT DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED Have the FREEZE FRAME DATA (Mode 2)/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS (fuel system related) been recorded?	Yes	Go to the next step.
2		No	Record the FREEZE FRAME DATA (Mode 2)/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS on the repair order, then go to the next step.
3	VERIFY RELATED REPAIR INFORMATION AVAILABILITY Verify related Service Bulletins and/or on-line repair information availability. Is any related repair information available?	Yes	Perform repair or diagnosis according to the available repair information. If the vehicle is not repaired, go to the next step.
3		No	Go to the next step.
4	VERIFY RELATED PENDING CODE AND/OR DTC Switch the ignition to off, then to ON (engine off). Perform the Pending Trouble Code Access Procedure and DTC Reading Procedure. (See ON-BOARD DIAGNOSTIC TEST .) Are any other PENDING CODEs and/or DTCs present?	Yes	If misfire DTC is present: Go to Step 11. If other DTC is present: Go to the applicable DTC inspection. (See DTC TABLE .)
4		No	If drive ability concern is present: Go to Step 11. If drive ability concern is not present: Go to the next step.
5	VERIFY CURRENT INPUT SIGNAL STATUS Access the following PIDs using the M-MDS: (See ON-BOARD DIAGNOSTIC TEST .) APP1 APP2 ECT MAF TP REL VSS Is there any signal that is far out of specification when the ignition is switched to ON and the engine runs? (See PCM INSPECTION .)	Yes	Inspect the suspected sensor and related wiring harness. Repair or replace the malfunctioning part according to the inspection results, then go to Step 20.
5		No	Go to the next step.
6	VERIFY CURRENT INPUT SIGNAL STATUS UNDER FREEZE FRAME DATA (MODE 2) CONDITION CAUTION: While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Access the same PIDs as in Step 5 while simulating under the FREEZE FRAME DATA (Mode 2) conditions. (See ON-BOARD DIAGNOSTIC TEST .) Is there any signal which causes drastic changes?	Yes	Inspect the suspected sensor and related wiring harness. Repair or replace the malfunctioning part according to the inspection results, then go to Step 20.
6		No	Go to the next step.
7	INSPECT A/F SENSOR HEATER Inspect the A/F sensor heater. (See AIR FUEL RATIO (A/F) SENSOR INSPECTION .) Is there any malfunction?	Yes	Replace the A/F sensor, then go to Step 20. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION .)
7		No	Go to the next step.
8	VERIFY CURRENT INPUT SIGNAL STATUS OF A/F SENSOR Reconnect all disconnected connectors. Inspect the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR INSPECTION .) Is there any malfunction?	Yes	Go to the next step.
8		No	Go to Step 11.
9	INSPECT INSTALLATION OF A/F SENSOR Inspect installation of A/F sensor. Is the A/F sensor installed securely?	Yes	Go to the next step.
9		No	Retighten the A/F sensor, then go to Step 20. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION .)
10	INSPECT FOR LEAKAGE FROM EXHAUST SYSTEM Visually inspect for exhaust gas leakage between exhaust manifold and A/F sensor. Is there any leakage?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to Step 20.
10		No	Replace the A/F sensor, then go to Step 20. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION .)
11	VERIFY CURRENT INPUT SIGNAL STATUS OF MAF SENSOR Start the engine. Access the MAF PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST .) Verify that the MAF PID value changes quickly while increasing (racing) the engine rpm. Is the MAF PID value normal? (See PCM INSPECTION .)	Yes	Go to Step 13.
11		No	Go to the next step.
12	INSPECT FOR EXCESSIVE AIR SUCTION OF INTAKE AIR SYSTEM Visually inspect for loose, cracked or damaged hoses on intake air system. NOTE: Engine speed may change when rust penetrating agent is sprayed on the air suction area. Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to Step 20.
12		No	Replace the MAF/IAT sensor, then go to Step 20. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION .)
13	INSPECT PURGE CONTROL SYSTEM OPERATION Perform the Purge Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to Step 20.
13		No	Go to the next step.
14	INSPECT FUEL LINE PRESSURE Switch the ignition to off. NOTE: If the engine will not start, inspect the fuel line pressure with ignition switches to ON. Inspect the fuel line pressure with the engine is running. (See FUEL LINE PRESSURE INSPECTION .) Is there any malfunction?	Yes	If the fuel line pressure is too low: Go to the next step. If the fuel line pressure is too high: Replace the fuel pump unit, then go to Step 20. (See FUEL PUMP UNIT REMOVAL/INSTALLATION .)
14		No	Go to Step 17.
15	INSPECT FOR FUEL LINE LEAKAGE Visually inspect for leakage from fuel line between fuel distributor and fuel pump unit. Is there any leakage?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to Step 20.
15		No	Go to the next step.
16	INSPECT FUEL FILTER Visually inspect for foreign materials or stain inside fuel filter (low-pressure side). Is there any foreign materials or stain?	Yes	Clean the fuel tank and filter (low-pressure side), then go to Step 20.
16		No	Replace the fuel pump unit, then go to Step 20. (See FUEL PUMP UNIT REMOVAL/INSTALLATION .)
17	INSPECT IGNITION SYSTEM OPERATION Perform the Spark Test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION .) Is a strong blue spark visible at each cylinder?	Yes	Go to the next step.
17		No	Repair or replace the malfunctioning part according to the inspection results, then go to Step 20.
18	INSPECT ENGINE COMPRESSION Inspect the engine compression. (See COMPRESSION INSPECTION .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to Step 20.
18		No	Go to the next step.
19	INSPECT FUEL INJECTOR OPERATION Perform the Fuel Injector Operation Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to the next step.
19		No	Go to the next step.
20	VERIFY DTC TROUBLESHOOTING COMPLETED Make sure to reconnect all disconnected connectors. Clear the DTC from the PCM memory using the M-MDS. (See AFTER REPAIR PROCEDURE .) Perform the Drive Mode 03 (EGR System, A/F Sensor Heater, HO2S Heater, A/F Sensor, HO2S and TWC Repair Verification Drive Mode). (See OBD-II DRIVE MODE .) Stop the vehicle and access the ON BOARD READINESS TEST to inspect the Drive Mode completion status. Verify the FUEL_EVAL PID changes to yes. If not, perform the Drive Mode 03 (EGR System, A/F Sensor Heater, HO2S Heater, A/F Sensor, HO2S and TWC Repair Verification Drive Mode). (See OBD-II DRIVE MODE .) Perform the KOER self test. (See KOEO/KOER SELF TEST .) Is the PENDING CODE for this DTC present?	Yes	Repeat the inspection from Step 1. If the malfunction recurs, replace the PCM. (See PCM REMOVAL/INSTALLATION .) Go to the next step.
20		No	Go to the next step.
21	VERIFY AFTER REPAIR PROCEDURE Perform the "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE .) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE .)
21		No	DTC troubleshooting completed.